onflict with B. in agreement with\r(2) Despite their short time on Earth, however, people have brought about enormous changes to\rthe surface of the planet O changes far____the interval of time they have occupied it.<Refer to\rPara. 5>\rA. in proportion to B. out of proportion to\r(3) Human activities can cause or permanent changes in natural systems.< Refer to Para. 12\r>\rA. speed up B. slow down\r(4) Now that they are the causes of the sickness of our planet, they seek ways to help the\rEarth, to give back what they take away.< Refer to Para. 15 >\rA. ignorant of B. aware of\rSection C Reduce, Reuse, Recycle\r1. Ask the students to read Section C within 10 minutes and finish doing exercises on Page 179\r2. Check on the answers.